Field of the Invention
The present invention relates to control of a liquid ejection head.
Description of the Related Art
A liquid ejection head like an ink jet print head includes a nozzle array having a plurality of nozzle parts for ejecting a liquid droplet by applying thereto a predetermined voltage pulse. In general, each of the nozzle parts includes a liquid chamber for accommodating ink, an energy generating element for applying energy for ejecting the ink inside the liquid chamber, and an ejection port from which the energy-applied ink is ejected as a droplet. Moreover, the liquid ejection head has a mechanism of refilling fresh ink into the liquid chamber according to an amount of missing liquid every time an ejecting operation is performed.
At this time, a refilling speed depends on the material and structure of the liquid chamber, and further depends on the physical properties of liquid. Moreover, in a case where the refilling speed is excessively low, for example, some time is required until preparation of a subsequent ejecting operation is completed, whereby a drive frequency must be set to be low. In contrast, in a case where the refilling speed is excessively high such that a meniscus overshoots from the ejection port, a surface of the ejection port may also be wet and may influence subsequent ejecting operations.
Japanese Patent Laid-Open No. H11-170524 (1999) discloses a method of suppressing long-period undulation of a meniscus along with an ejecting operation in the configuration of using a piezoelectric element as an energy generating element. According to Japanese Patent Laid-Open No. H11-170524 (1999), the piezoelectric element is driven to a direction of drawing back the meniscus while the meniscus heads for an ejection port, thereby dampening a long-period residual vibration of the meniscus along with the ejecting operation and suppressing its influence on subsequent ejecting operations.
Meanwhile, in a liquid ejection head using a thermal system which ejects a liquid droplet by bubble-growing energy generated by film boiling by use of an electrothermal transducer as an energy generating element, a force to draw back the meniscus cannot be generated by drive control. Accordingly, in the liquid ejection head using the thermal system, in general, a flow resistance is increased by adjusting the material or structure of the liquid chamber, and an overshoot of the meniscus is suppressed by reducing the refilling speed.
However, in a case of ejecting inks of different colors by a plurality of nozzle arrays, respectively, as in a color ink jet print apparatus, each of the plurality of nozzle arrays handles the liquid having a different physical property. As a result, even if each nozzle array has the same material and structure, a certain level of variation occurs in the refilling speed. To make the refilling speed uniform, the flow resistance can be adjusted by setting the material and structure differently by each nozzle array, but in this case, cost increase will be a concern. Further, even if such adjustment is made, there is a case, in recent printing apparatuses, where the same print head can be mounted on different types of printing apparatuses. In this case, the same nozzle array even must be adapted to the liquids having different physical properties depending on the type of printing apparatus in which the print head is mounted, and thus, it is difficult to adjust the refilling speed by changing the material and structure of the liquid chamber.